Improved door-bolt



UNITED STATES PATENT OEEIOE.

GEO. T. ALLAMBY, OE BANGOR, MAINE.

IMPROVED DOOR-BOLT.

Specification forming part of Letters Patent No. 57,616, dated August28, 1866.

To all whom it may concern:

Be it known that I, GEORGE T. ALLAMBY, of Bangor, in the county ofPenobscot and State of Maine, have invented an Improved Door-Bolt; and Ido hereby declare the saine to be fully described in the followingspecication and represented in the accompanying drawings, of which-Figure l is a top view, Fig. 2a longitudinal section, and Fig. 3 atransverse section, ot' it. Fig. 4 is an elevation ot' the front plateand the curved slot thereof of the bolt-case.

' In the said drawings, A denotes a spring'- bolt arranged within acase, B. The front plate, a, of the said case has a curved slot, b,formed through it, and shaped in manner as seen in Fig. 4. ln rear ofthe said slot there is a covering-plate, c, which rests against the rearside ot' the plate a, and is fastened on the shank (l ot1 a knob, C, thesaid shank being extended through the slot b and into a recess,

-e, formed in the end ot' a short arn1,f, which projects from thespring-bolt A. The said bolt A is to be capable not only ot' being slidlongitudinally, but of turning freely in a transverse direction withinthe case B or the end parts, g g, thereof, the spring h,`envelopin g thebolt7 having one end aga-inst the case and the other against the arni f.

While the bolt may be in the act ot' being shot forward by pressureapplied to the knob the shank of the latter will be moved downwardjntothe lower part, b, of the slot b, andsuch lower part, while the shankmay be within it, will serve to lock the bolt or prevent it from beingretracted. By raising the knob out of the part b and into the Lipperpart of the slot the spring will be free to act and force the bolt backwithin the case. During the movement of the knob the slot will becovered by the plate c.

The great advantage of my improved bolt over the common bolt, whose easehas one or more notches leading` out of its knob-shank slot, .and forlocking the bolt, and which bolt so made I do not claim, is the greatersecurity which it offers against any attempt of a per son on the outerside of the door to force the bolt backward, as the part b of theslotwill operate to prevent the bolt from being revolved, which it mustbe preparatory to being forced back by the spring. Besides this, myimproved boltpossesses other important advantages.

I claiml. The combination of the socketed arm f, or its equivalent, withthe bolt A, applied to the case, as explained. the separate knob G, itsshank d, and the curved slot b, inade'in theA bolt-case, the whole beingarranged substantially in manner and so as to operate as described.

2. The combination ot the covering-plate o, the slot b, the shank d, theknob c, and the socketed arm j', as applied to the bolt and its case,the whole being arranged substantially in inanner and to operate asexplained.

GEO. T. ALLAMBY.

Witnesses:

GIIAs. F. SMITH,

H. E. LOVEJOY.

